Many countries have adopted tile metric measuring system for tile manufacture of bolts, screws: nuts and wrenches. Such countries as France. Germany, Italy, Japan, Czechoslovakia and Russia today almost exclusively utilize the metric system for such manufactures. The United States, Canada, England, Australia, New Zealand and the like, use measuring systems based upon both the English (inch) and metric measuring systems.
National standards or specifications have been adopted by many technically developed countries for sockets and other wrenches. These standards, which differ at least in part from one another, include SAE, ASTM, MIL, GGG-W, BS, FS, DIN, JS, CSN, JUS, and COST. No uniform international standard has yet been accepted, although more than fifteen years have been devoted to the effort to reach a standard acceptable to all technically developed countries. Great Britain, for example, presently uses up to six different systems for marking spanners, sockets and other wrenches. The United States predominantly uses tile English (inch) system (AF, ANSI, MIL and SAE) and, to some extent, the metric system (millimeters). The diversity in such standards has limited the development of new types of bolts, nuts and wrenching tools. Periodic reviews and revisions of such standards have not produced the necessary changes to cover rapid development of a new type of wrenches, and the issuance of new, updated standards often takes over fifteen years. Consequently, a vast number of different wrenching tools of various designs, openings and tolerances are manufactured throughout the world. A user is subjected to a never-ending inventory of wrenching tools to accommodate all of the sizes and measuring systems in existence today. This is costly and inconvenient for individuals and for industry in general.
One attempt to simplify this situation is found in U.S. Pat. No. 4,100,824 which describes a wrench with a non-uniform interior configuration having one set of grooves sized in tile English system and another set of grooves sized in the metric system. This patent does not address the problems created through tile use of various additional measuring systems. Care needs to be taken with this system to insert the bolt or nut head in the correct set of grooves, and this wrenching system moreover generally is not suitable for use in impact or power sockets or in open end wrenches and British sized spanners and sockets.
U.S. Pat. No. 3,027,790 discloses a wrench having several moving parts as adaptors and does not appear to represent a practical solution to the problem, since professionals and serious amateurs appear to prefer solid one-piece wrenching tools with no extraneous parts.
It would be desirable to provide simplified rotary wrenching tools having the ability to drive one or more and, desirably, up to six different sizes of fasteners, and wrenches having better performance in bearing action in tightening or loosening fasteners without damage to either the tool or the fastener.